1. Field of the Invention
The present invention relates to a fluid convection heat dissipation device, and in particular to a heat dissipation device that is applicable to an electronic device for generating repeated circulation of enclosed fluid by convection to realize heat dissipation.
2. The Related Arts
Conventional light-emitting diode (LED) based lighting elements have been widely used in applications of environmentally conservative lighting devices or illuminating devices. A major challenge to the LED based lighting devices or illuminating devices is dissipation of heat. In a regular environment, the temperature of an LED in giving off light is that the temperature inside the LED package is around 4-50° C. However, in applications of high power lighting, the internal temperature of the LED package might get as high as 100-120° C. Unless the heat can be properly dissipated, a junction of the LED element may get very high. FIG. 1 of the attached drawings illustrates a temperature distribution curve of the junction of an LED in giving off light. In FIG. 1, the abscissa axis R of the temperature distribution curve F represents the radius of a heat distribution area around the junction of the LED and the ordinate axis T indicates temperature. The following formula is known for describing the curve:Tjunction=R×θjunctoin−ambient×W+Tambient
In other words, as indicated in FIG. 1 and described as the above formula, if the temperature of the junction of an LED continuously maintains at a high temperature, the lifespan of the LED may be shortened.
Conventional heat dissipation modules for light-emitting diodes, such as finned heat dissipation modules, have poor performance and non-uniform heat dissipation. In other words, such conventional heat dissipation modules use the fin to radiate heat into the surroundings and theoretically, the temperature and the thermal energy dissipated are high at a location close to the heat spot. The surrounding air is heated to a high temperature, making the air molecules moving fast and thus leading to poor heat dissipation performance for the fins that are close to the heat source. Even a sufficient number of fins that is calculated on the basis of known theories is provided, the heat dissipation for LED realized by such a mechanism must be assisted by turbulence of air caused by a fan. Since the fan consumes power, which is not considered environmental protection, and failure of the fan may happen, using a fan to assist heat dissipation is not a good solution. In addition, the arrangement of a fan makes the heat dissipation module bulky, which is not advantageous for applications of lighting devices.
Known techniques, such as Taiwan Patent Publication No. I299081, teach improvement of heat dissipation performance by employing internal baffles and interference elements. However, such a known techniques does not help in bringing heat away. In addition, a heat sink and a fan must be arranged at a remote end to carry out second-time heat dissipation. Apparently, such a known technique has a complicated structure and high costs and still suffers the problems of failure of fan and pump, and it is not applicable to a dedicated and small-size LED-based lighting device.